Condenser and separator for wood-impregnating retorts



j. H. DUNSTAN ANB R. HAVES.

ND SEPARATGR FOR WOOD lMRBEGNATING REWETS.,

APNIC/more FILED ocT.-"aa.1919.

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JOHNH. DUNSTN v.AND RBERT A. DAVIS, Oli' SIDELL, LOUISIANA.

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Specification of Letters Patent.

Paten-ted Apr. 5, 1921;

Application led. ctober 13, 1919. Serial No. 330,51. i

To all whom t may cof/weint:

Be it known that we, JOHN H. DUNsrAN and ROBERT A. Davis, of Slidell in the county of Saint Tamm-any and `otate ci' Louisiana, have invented certain new and useful Improvements n.Co1idensers and .retort which is then 4closed to make it practically air-tight. Live steam is next admitted into the retort until the pressure of the steam in the retort reaches from 2O to 30 pounds per square inch,` with a correspondino temperature of from 250 to 275 degrees -This pressure and temperature are maintained in the retort. until'the timber is heated to this temperature throughout. retort as quickly as possible and a vacuum or" as high degree as possible is created rin the retortin the quickest possible time. The

object of this Vacuum is as lfollows: vWhen the steam is blown out of the retort by its own pressure the temperature of the wood with its contained moisture has a temperature of Afrom 250`to 275 degrees F. The boiling point ofwater at atmospheric pressure being 212 decrees F.; its boiling point is only 30 degrees at 30 inches of vacuum, (a perfectvvacuum). Therefore the nearer we come to obtainin aperfect vacuum the lower thefboilingpoint of water under the vacuum. l

By obtaining a high and quick vacuum within the retort the boiling point of tlie water contained in the wood is lowered and this water s vaporized and drawn from the wood and carried oli through the condenser. It is most essential that this vacuum be created quickly as otherwise the wooddn the retort will lose its heat by radiation so that the temperature within the retort will be below the boiling point under theexisting vacuum.

After the moisture is extracted from the The steam is then'blown out ot the timber the retort is lilled with oil, such as coal tar creosote, and more of this oil is, pumped into the retort under pressure until the timber amount.

In practising under Letters Patent No. 831.4150, issued September 18, A1906,'011 the application of Cuthbert B. Lowry, and other processes, a second high quick vacuum is necessary after the injection for' theoil so as to virtually withdraw the oil from the cells and pores. of the timber, the portion remaining being completely absorbed, thus leaving no free oil and consequently avoiding waste has absorbed the required of' material.

' Fromthe foregoing it will be seen that one of the most important essentials to successful creosoting is the immediate creation of the highest attainable degree of vacuum, We have experienced difficulty in the use of' the 'machinery heretofore proposed for quickly establishing this high vacuum.

lVhen a dry vacuum pump is connected to an vordinary engine. steam condenser, or the condenser is used alone, and no appreciable quantity of air or other non-condensable gas is present,v the vacuum may readily be created. In the retort used in wood impregnation, however, air and non-condensable gases are present besides the steam. These'tend to carry the condensing water with them over to the pump which has to be used to create a prompt and high vacuum. This injures the dry pumpv and necessitates the use of ya wet vacuum pump which is an expensive structure constantly becoming deranged.

Te have overcome the difficulty by the structure illustrated conventionally in. the4 drawing. where a barometric condenserl l,

having a water inlet pipe 2, is adapted for to the side and interior ofthe separator and its inner end opens downward in the' separator, while a second pipe 8. establishes direct communication between the top of the separator and a vacuum pump. The outlet -ifoo tremity constantly submerged in` thehot well which is equipped with an overiowl The outlet pipes 4 and are in 'length not less than 3.3 feet to overcome the tendency' of. the suction createdfby the vacuum to Y -draw'the water from the hot well and to diameter or" pipe .7

allow the water to discharge constantly from the separator. The cross sectional area of the separator is materially greater than the at the extremity which opens downward into the separator. In consequence when the water and non-condens- ;.able gases reach the separator the velocity of their flow is, greatly reduced and the force of the momentum acquired. by the water its flow','together with the force of gravity, causes themater to fall to the bot-tom of the separator (located well below the outlet of pipeV 7) audible carried ofi through the sealed pipe 9,v while theair and gases "have toV reverse their direction of travel and be drawn to the top of the separator;

and through pipe 8 to the vacuum'pump, their upward travel allowing further opportunity for particles of moisture to gravi- Y pregnation.l

tate out of the stream. Thus it is practically impossible for the air and gases to carry water to the pump. The water accumulating -in hot well 5 overflow 10.

We are/aware that it is not broadly novel to proyide a separator between a condenser and vacuum pump; but we are not aware of y such structure prior vto ours which is available for use in the art of wood im- Means have heretofore been provided for regulating a vacuum proportionate to the quantity and temperature tof the water employed for condensation and the steam to be condensed. This has been accomplished by' conducting the hot water from the separating chamberinto the condensing chamber to control the tempera- .ture of the fresh water in the condenser. All such constructions are foreign to our purpose. Te'seek to create a vacuum as quickly and as high as possible. Our conpasses out` through the denser is directly connected tothe retort and to the separator andthe separator is directly connected to the pump. The water discharged from both of themis waste.

Likewise those structures in which the pipe Jfrom the condenser enters the top of the Lara-,oca

9 .of the separator also -has its lower eX- largest area ofthe separator, from der-rn:

ward, then up past 7 to the top and Iout at 8, reducing velocity and effectively eiinnnat-Y in'the means for allowing the water to con-- stantly discharge from the separator. In the first fifteen minutes of vacuum period the iiow Yotwater into the separator is approximately 300 'gallonsY per minute. Manifestly a continuous discharge from the separator is essential in order to deal with this iiow and at the same time avoid breaking the vacuum. By arranging our separator at a height ofat least 33 feet above the hot well the vacuum does not interfere with'the reeand constant iowirom the condenser Yand separator. The ordinary commercial types of separators having means for periodically discharging the water would not be available for our use. may allow of discharging while under pressure but the. cannot discharge while under vacuum as opening them to the atmosphere would break the vacuuinl Vire claim as our invention: i

l. Means for creating a high and quick vacuum in a wood impregn ating retortcom- Yprising a wood. impregnating retort, a harometric condenser connected therewith, a barometric separator, a pipe from the con- `denser discharging into the side of the sepa-V ing downward fromsaid separator having its extremity submerged in said hot well, whereby said separator may constantly discharge while under a vacuum.

2. Means orcreating a high and quick vacuum in a wood impregnating retort comprising a wood iinpregnating retort, a bar-` ometric condenser connected therewith, a

vertically disposed barometric separator, a pipe from the condenser entering the side of the separator and discharging downward, a pipe constantly maintaining communication between the top of the separatorand a vvacuum pump, a subjacent hotwell7 and discharge pipe leading downward from said condenser landseparator having their' extremities submerged in said hot well.

3. Means for creating a high and quick vacuum-in a wood impregnating retort comprising a wood impregnating retort, a barometric condenser connected therewith, a b'arometric separator, apipe7 from the condenser discharging into the/separator, a pipe constantly leading directlylifrom the separator to a vacuum pump, a hot well, and discharge pipes leading downward from said condenser and separator having their extremities submerged in said hot well.

1i. Means for creating a high and quick vacuum in a wood impregnating retort They iio

comprising a wood impregnating retort, a pump, a; hot Well, and discharge pipes leadbarornetric. condenser connected therewith, A ing downward fromsaid condenser and sep- 1 a barometrie separator, a pipe from the con- -arator having their extremities submerged .denser discharging into the separator, -in said hot Well.

means for directing 'the flow Within the lIn testimony 'whereof We 1 have signed separator to separate the Water from the this specification.

'air and gases, Ya pipe constantly leading di- JOHN H. DUNSTAN. rectly from the separator to a vacuum ROBERT A. DAVIS. 

